I had to turn visitors off for now, or at least until I patch to the latest release.. Those BoS visitors kept coming, I think last time I was at Abernathy I had more BoS soldiers around then there are on Prydwen and in airport combined. Could have formed my own "Brotherhood of <some other metal>".
EDIT: turning visitors off and leaving area for a while and coming back later did not clear the BoS members, they still hang around. A lot of them. Which is good for security for time being, I guess, but if I would happen to choose BoS side in main story and alienate Danse with BoS, I suspect this would end up with a huge war at Abernathy's, should I go there with Danse (and if they don't leave the area).
EDIT 2: Below is the image of BoS members at Abernathy (assuming the link works, pic is on Steam), note that this is not all of them, there's plenty of BoS to the sides, behind me, inside the house, behind the house, way to left on pasture, etc.
Nah link didn't work, see if I can upload the image..
EDIT 3: Does anyone have any idea how I can get rid of this BoS army at Abernathy? I took Danse away as the leader, left for few days and came back, that made no difference - I still have about 6-7 vertibirds parked around the farm, one flying around it patrolling in air, almost three times as many BoS soldiers around as there are in Boston airport and Prydwen combined. Assigned Codsworth as the new leader, no difference so far. Vistors already disabled, disabled animals and extra NPC's - nope. Heck I even summoned a whole bunch of sentry bot level angry automatrons but BoS forces are there in such a number that they killed them all and only one BoS soldier died. From explosions of wrecked robots. However, almost all fields and some water purifiers got blown up in crossfire, so I had to refresh and fix those afterwards.. Do I have to blow up my whole level 3 settlement or something to get rid of them? I don't want to outright shoot them either, since I am in good terms with BoS and removing them via console isn't something I would like to do either.